EIderly falls constitute one of the most costly health problems in the U.S., both in terms of expense to the healthcare system and in individual suffering. Fully one-third of people over age 65 fall each year, many incurring significant injuries that strongly impact their long-term health prospects and productivity. Although many factors contribute to the propensity of the elderly to fall, it has been clearly shown that loss of peripheral sensation (particularly in foot sole and lower extremity muscles and joints) is key among them. A technology that directly improves peripheral sensation would be instrumental in combating elderly falls. Developing this technology is the long-range goal of this program. Stochastic resonance (SR) is a counterintuitive phenomenon in which slight amounts of noise presented to a system increases its ability to discern weak signals or stimuli. Many researchers have shown that SR can improve the performance of sensory systems in animal models and human subjects. Afferent Corporation's Phase I SBIR research demonstrated that SR-based stimulation of foot-sole significantly improved balance in elderly subjects. The goal of this proposed research is to advance the Phase 1 results toward a commercially realizable stimulation system to improve the balance and gait of elderly. The work will focus first on the development of pre-production fully functioning models of an insole that provides mechanical SR stimulation. The functional benefits of these devices will be tested in three ways: (1) standing balance (quiet and perturbed), (2) adaptation following prolonged exposure, and (3) gait (normal and perturbed) and mobility. Both healthy elderly and elderly subjects who are known to suffer from instability and falls will be studied. Established, quantitative measures of balance, gait, and mobility will be used to analyze results from trials that are blinded to both the subject and the technician performing the experiment. The results gained from this program are expected to motivate a full-fledged product development effort, regulatory filings, and market introduction.